1. Field
Inventive concepts of example embodiments relate to semiconductor memory devices, for example, semiconductor memory devices having a bit line disposed on a memory block without a complimentary bit line, and methods of sensing and amplifying data thereof.
2. Description of the Conventional Art
Conventional semiconductor memory devices, such as dynamic random access memory (DRAM), have a plurality of memory blocks and a plurality of sense amplifiers between memory blocks. Each memory block includes a plurality of memory cells, and is connected to one of a plurality of column lines and one of a plurality of row lines.
Most conventional semiconductor memory devices have either a folded bit line structure or an open bit line structure. A sense amplifier having a folded bit line structure senses the voltage difference between two bit lines disposed on the same memory block using one of two bit lines as a complementary bit line. A sense amplifier having an open bit line structure senses the voltage difference between two bit lines disposed in different memory blocks using one of the two bit lines as a complementary bit line. In each case, however, the sense amplifier uses a complimentary bit line.
Recently, the open bit line structure has been more widely adopted because the open bit line structure integrates more memory cells in the same area. However, a semiconductor memory device using the open bit line structure must have dummy cells in edge memory blocks disposed at both sides of the memory blocks.
Also, bit lines need to be pre-charged to a constant voltage level before beginning a read operation of a sense amplifier. Conventionally, there are three ways to pre-charge bit lines; a half power supply voltage ½ VDD pre-charge scheme, a power supply voltage VDD pre-charge scheme and a ground voltage VSS pre-charge scheme. As demand for lower power semiconductor memory devices grows, the power supply voltage VDD pre-charge scheme and the ground voltage VSS pre-charge scheme have been more widely studied. The ½ VDD pre-charge scheme, however, has not.